> I also don't grasp the logic behind the notion that once a creator shows his work -- or work-in-progress -- to the public that he is somehow bound by duty, honor, respect for his 'followers', or some other compelling consideration, to finish that work.
You can show off your work in any way that you want. You are also not bound by duty or anything else to finish that work. However, if you are putting it out there for other to see and or use, at least say that this may or may not be useful in some way. To cover yourself, you could say that it will be a work in progress and that the progress will move in fits and starts as you have time to devote to it. At that point, there will never be a need to say that you are giving up on it.
Bad comparison with Beethoven. But to answer your question, if he had said that this is the first movement and may have a potential to be completed if the Duke commissions it, then it doesn't reflect badly on him when the Duke doesn't commission it.
It is a matter of what expectation you are creating in those who are viewing your work. If you are saying that it is there as an example of something, then so it is. But if you go out and say "here is the bee's knees", and then you decide that it is no longer worth your while because the amount of work is now too much, then you have created the problem for yourself.
There is a project called Axiom, which has inspired me to look at my own code and projects in a different light. But to follow in the footsteps presented by Axiom in my own projects involves a lot of tedious hard work. The benefit that I see is that anyone who comes after me and is interested in what I have done will be able to follow. That "anyone" may only ever be me, so be it.